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ENSO & SST

ENSO and Sea Surface Temperatures

Equatorial Pacific Ocean up to +1.5°C warmer than average

El Niño likely if conditions persist

In the tropical central Pacific, a band of anomalously warm water (+1.5°C above average) extends from Western Kiribati towards the coast of South America. An area of the Pacific which is also very much warmer than average lies southeast of Pitcairn Island (+2.0°C above average).

Generally, most of the Southwest Pacific is warmer than average ( +1.0 to 1.5°C). Notably, there is no typical cold ‘horseshoe’ SST anomaly in the Western Pacific which is usually present during an El Niño.

Equatorial SSTs continued to increase through June within NINO3 and NINO 4 (+1.0°C and +1.2°C above average respectively) regions. During June there has been an expansion of the warm SST anomalies across the equatorial Pacific towards Eastern Pacific. The conditions in the Pacific Ocean have rapidly changedover the last month significantly increasing the probability of an El Niño.

The warmer Equatorial SSTs and weakening tradewinds are the main factors that led to an increased possibility of an El Niño. It is likely that this phenomenon will affect much of the Southwest Pacific climate later this year. Some areas have already experienced reduced rainfall (parts of southwest Pacific) and other areas have had enhanced rainfall (Kiribati).

Sea surface temperature anomalies (°C) for June 2002

Mean sea surface temperatures (°C) for June 2002